The purpose of this study is to control the emerging weeds in rice at vegetative growth under the System of Rice Intensification (SRI) technique using chemical methods of weed management practices and also to determine the weed flora in the experimental field, its nutrient uptake from the soil, phytotoxicity, and the production potential of rice. A Randomized Block Design with three replications was used to conduct the experiment. There were eight treatments: T1-Control (unweeded), T2-Hand weeding twice at 20 and 40 DAT, T3-Cono weeding twice at 20 and 40 DAT, T4-Butachlor (1.25 kg ai/ha), T5-Thiobencarb (1.8 kg ai/ha), T6-Pretilachlor (0.5 kg ai/ha), T7-Oxadiazon (0.75 kg ai/ha), and T8-Pyrazosulfuron ethyl (0.0015 kg ai/ha). Each plot’s sampling strip was used to collect data on weed count and dry weight at 30 and 60 days after planting. Rice yield metrics were estimated after harvest, and visual observations were used to measure the phytotoxicity of herbicides in rice crops. The findings showed that three grasses, two sedges, and two broad-leaved plants made up the majority of the weed flora associated with transplanted rice. Pretilachlor is a pre-emergent herbicide that has been shown to be an effective weed control strategy in the chemical weed control method by suppressing weed density and dry mass. The findings were comparable to those of manual hand weeding and mechanical cono weeding. Cultivated weed management, including hand and mechanical weeding, is tiresome and labour-intensive, so the use of chemical methods such as pre-emergence herbicides can cost-effectively suppress weeds in SRI-grown rice.
Key words: Rice, Pretilachlor, System of rice intensification, phytotoxicity.
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